(20 U.S.C. 6301 et. seq.), as amended by this Act, from programs. authorized under the Elementary and Secondary Education Act. of 1965 (20 U.S.C. 6301 et seq.), as in effect on the day before. the date of enactment of this Act.
The efficacy of a vaccine is different from its effectiveness. It is dependent on several factors such as: 1  adherence to vaccine schedules. 2  the disease â some diseases have vaccines against them that perform better than for other diseases. 3  the strain of vaccine â some vaccine strains are more effective than others.
Vaccine Effectiveness. By Dr Ananya Mandal, MD. Vaccines help the body remember a microorganism to be able to fight it off when the need comes. However, vaccines are not fool proof and do not guarantee complete protection from a disease. This could be due to various reasons.